Rolling bearings are already known which can accommodate both radial forces and axial forces. Said rolling bearings are designed, for example, as angular-contact ball bearings or angular-contact roller bearings, with the respective rolling bodies being arranged between a bearing inner ring and a bearing outer ring which, for this reason, have relatively large radial dimensions. It is considered to be a further disadvantage in particular of angular-contact roller bearings that the axial forces are transmitted between the bearing rings and the rollers via flanges formed on the bearing rings, such that bearings of said type have comparatively high internal bearing friction. Furthermore, the functions firstly of radial mounting and secondly of axial mounting cannot be separated from one another, such that, for example, the occurrence of axial play as a result of thermal expansion of the bearing or of the components which are connected thereto will always also have an effect on the radial play.
Also already known are combined radial-axial rolling bearings of the type specified in the preamble of claim 1 which comprise in each case a radial bearing unit and an axial bearing unit which is connected to but functionally separated from said radial bearing unit. DE 691 14 224 T2 presents a radial-axial rolling bearing of said type for mounting a radially stepped shaft, in which radial-axial rolling bearing the radial bearing unit is designed as a needle bearing and is assigned to the circumference of the smaller diameter, and in which radial-axial rolling bearing the axial bearing unit which is assigned to the axial surface is designed as a ball bearing whose raceways are formed firstly by an axial bearing ring which bears against the axial surface of the shaft and secondly by a separate raceway ring which bears against an axial surface of the housing. The axial bearing ring and the radial bearing ring are not directly connected to one another and to the raceway ring which is required for the function of the bearing, and therefore said bearing does not form a structural unit and, for example, cannot be assembled in one work step. Furthermore, the known bearing is not suitable for shaft housing designs in which the radial bearing unit is to be assigned to the respectively larger diameter.
A similar radial and axial bearing in which the radial bearing unit is likewise assigned to the circumferential surface with the smaller diameter is presented, for example, in DE 2 600 955.
The patent AT 310 510, in particular FIG. 6 thereof, has duly already disclosed a combined radial-axial bearing in which the radial bearing unit is assigned to the circumferential surface of the larger diameter. Here, however, the radial bearing unit and the axial bearing unit are arranged in a single bearing shell which is common to both bearing units, such that here, too, complete separation of the radial bearing function and the axial bearing function is not provided.